7 ms·

This is so neat! Few questions though, if anyone can answer: 1) The cable still looks pretty thin, is it being housed in some sort of protective layer/tube bef

by lprd 8y ago

This is so neat! Few questions though, if anyone can answer: 1) The cable still looks pretty thin, is it being housed in some sort of protective layer/tube before it is laid? Seems like an anchor snag could easily break that line. If that happens, is it possible to 'patch' a fiber cable? 2) Once it nears the coast, how deep is the line being buried? 3) This may be a dumb question (I'm no engineer), but does the light travel from the source all the way to end without any "relay" mechanism? 4) How much bandwidth can travel through one of these lines?

lota-putty 8y ago
5) Does anyone know how to save that(cabling-world) animated image alone? All I can make out is 'g-map' div ;-)
- Moru 8y ago
  Make window fullscreen, press Windows-G on a Windows 10 computer with halfway good graphics card. Pump it into VLC and crop away the stuff you don't want ... and profit? :-)
- factsaresacred 8y ago
  Here you go: https://giant.gfycat.com/UnderstatedLinedBird.gif https://giant.gfycat.com/UnderstatedLinedBird.gif
- est31 8y ago
  That animated image is made up of a canvas background of the world and an SVG foreground of the cables. Both are created using js from downloaded json data, ne_110m.json and fusion-cables-2019-02-27-simplified.json. Quite tough to get that into something that's not using pixel graphics and self-contained (aka only displaying the stuff in the page).
lb1lf 8y ago
1) The fibre pairs are housed in multiple layers of armor to protect against the elements, supply power to inline amplifiers and -most notably- provide the structural strength needed to survive being deployed. Outside diameter is still less than one inch, though. 2) Depends, but a metre or two (tops!) would be the right ballpark. 3) Not a dumb question; while loss in fibre optic cable is very low, repeaters are installed at regular intervals along the cable. they are powered by high-voltage DC supplied through the cable armor. The ocean acts as the return path. 4) Lots.
- bogomipz 8y ago
  >"3) Not a dumb question; while loss in fibre optic cable is very low, repeaters are installed at regular intervals along the cable. they are powered by high-voltage DC supplied through the cable armor. The ocean acts as the return path." That's incorrect, amplification is done via Erbium doping, it is part of the core of the cable. There are no external repeaters.
  - lb1lf 8y ago
    ...but the erbium doping is only part of the equation, involving additional circuitry powered from the surface? Or have I misunderstood completely?
    - turboman 8y ago
      So to clear this up a bit. EDFAs (which are the in-line amplifiers which use erbium doping) work by having a section of a fiber doped with erbium ions. Only the part which is going to amplify the signal is doped, the rest of the fiber is supposed to be as clean as it gets. Those erbium ions get shot with a laser (that's the part that needs power from the shore) and get excited. The source signal then hits the ions, which then emit more photons of the same exact properties, but just way more of them - therefore the amplification part. Continue 80km down the line, and the same thing has to happen again, as enough light has been attenuated. I mostly work with land systems, where the EDFAs are pieces of equipment completely separated from the fiber - you get a normal strand of fiber dug into the ground, and once you want to amplify it, you've got to plug it into an EDFA line card with the erbium-doped fiber already contained in it. In the sea, those systems are way more integrated and the fiber is usually spliced right into the amplifier. I might be able to dig up a card tomorrow if you're curious as to how the system looks.
      - MacroChip 8y ago
        Yes please! Thank you
      - lb1lf 8y ago
ioulian 8y ago
1: I think they don't put that thin cable on the seafloor, they are bunched together, in a much bigger cable with a lot of stuff around it [0] to protect it. About the patching, they say that in the article: they sometimes cut the cable (in case of a bad weather) and attach it to a buoy. So they can "patch it" ;) [0] http://2oqz471sa19h3vbwa53m33yj-wpengine.netdna-ssl.com/wp-content/uploads/2017/08/cable-cross-section.jpg http://2oqz471sa19h3vbwa53m33yj-wpengine.netdna-ssl.com/wp-c...
jlgaddis 8y ago
I'm on an iPad at the moment so I can't give you a direct link to any videos, but search for Hibernia Atlantic on Youtube. They have some short videos showing how the cables are laid, repaired, and so on.
rassibassi 8y ago
Recent graduate in Optical Communications here :) 1) The fiber is pretty thin, but there are several fibers combined in one transoceanic cable, see here https://en.wikipedia.org/wiki/Submarine_communications_cable https://en.wikipedia.org/wiki/Submarine_communications_cable. They don't patch them, but splice the fibers. Patching introduces a little loss, so it should be avoided. 2) Not sure how deep they are buried, but I think to remember that the shore end of a submarine cable is better protected than the part in the deep ocean. Due to more ship traffic at the coast etc. 3) Good question. The loss of an optical fiber is roughly 0.2 dB/km. Across the ocean the optical signal must be amplified several times (every 80-100km). Nowadays the amplification is all optical (EDFA or Raman). Before there were electrical regeneration schemes. Check out the history of the field, it's is quite interesting [1]. 4) Not sure how much data such a cable can carry, since it depends on how many fibers are deployed within. However, there are multiple interesting things to look into here. In research labs, people are investigating multicore/multimode fibers (space division multiplexing) [2], these fiber have incredible capacity. Personally, I think the most interesting metric is the spectral efficiency, so how much data can be transmitted per second per Herz. Such a metric is independent of multiplexing schemes over space/wavelength/time, and improvements have to come from better devices, signal processing or signal shaping methods [3]. Another mind-blowing area is using the nonlinear Fourier transform for better signaling methods [4]. Feel free to ask more questions :) and checkout the two biggest conferences for more in depth info. https://www.ofcconference.org/en-us/home/ https://www.ofcconference.org/en-us/home/ https://www.ecocexhibition.com/ https://www.ecocexhibition.com/ [1] https://www.osapublishing.org/oe/abstract.cfm?URI=oe-26-18-24190 https://www.osapublishing.org/oe/abstract.cfm?URI=oe-26-18-2... [2] Multicore: https://ieeexplore.ieee.org/abstract/document/7341685 https://ieeexplore.ieee.org/abstract/document/7341685 Multimode: https://www.osapublishing.org/abstract.cfm?uri=ofc-2018-Th4C.4 https://www.osapublishing.org/abstract.cfm?uri=ofc-2018-Th4C... Multimode+core: https://ieeexplore.ieee.org/document/8535233 https://ieeexplore.ieee.org/document/8535233 [3] https://arxiv.org/abs/1606.04073 https://arxiv.org/abs/1606.04073 [4] https://www.osapublishing.org/optica/abstract.cfm?uri=optica-4-3-307 https://www.osapublishing.org/optica/abstract.cfm?uri=optica...
- lprd 8y ago
  Looks like I got some reading material for tonight! Really appreciate your response, this is all very fascinating to me. Cheers :)
apaprocki 8y ago
4. Undersea should be the same as under land — 9.6Tbps, 96 100Gbps fibers.

by lprd 8y ago

lota-putty 8y ago

5) Does anyone know how to save that(cabling-world) animated image alone? All I can make out is 'g-map' div ;-)

Moru 8y ago
Make window fullscreen, press Windows-G on a Windows 10 computer with halfway good graphics card. Pump it into VLC and crop away the stuff you don't want ... and profit? :-)
factsaresacred 8y ago
Here you go: https://giant.gfycat.com/UnderstatedLinedBird.gif https://giant.gfycat.com/UnderstatedLinedBird.gif
est31 8y ago
That animated image is made up of a canvas background of the world and an SVG foreground of the cables. Both are created using js from downloaded json data, ne_110m.json and fusion-cables-2019-02-27-simplified.json. Quite tough to get that into something that's not using pixel graphics and self-contained (aka only displaying the stuff in the page).

lb1lf 8y ago

1) The fibre pairs are housed in multiple layers of armor to protect against the elements, supply power to inline amplifiers and -most notably- provide the structural strength needed to survive being deployed. Outside diameter is still less than one inch, though. 2) Depends, but a metre or two (tops!) would be the right ballpark. 3) Not a dumb question; while loss in fibre optic cable is very low, repeaters are installed at regular intervals along the cable. they are powered by high-voltage DC supplied through the cable armor. The ocean acts as the return path. 4) Lots.

bogomipz 8y ago
>"3) Not a dumb question; while loss in fibre optic cable is very low, repeaters are installed at regular intervals along the cable. they are powered by high-voltage DC supplied through the cable armor. The ocean acts as the return path." That's incorrect, amplification is done via Erbium doping, it is part of the core of the cable. There are no external repeaters.
- lb1lf 8y ago
  ...but the erbium doping is only part of the equation, involving additional circuitry powered from the surface? Or have I misunderstood completely?
  - turboman 8y ago
    So to clear this up a bit. EDFAs (which are the in-line amplifiers which use erbium doping) work by having a section of a fiber doped with erbium ions. Only the part which is going to amplify the signal is doped, the rest of the fiber is supposed to be as clean as it gets. Those erbium ions get shot with a laser (that's the part that needs power from the shore) and get excited. The source signal then hits the ions, which then emit more photons of the same exact properties, but just way more of them - therefore the amplification part. Continue 80km down the line, and the same thing has to happen again, as enough light has been attenuated. I mostly work with land systems, where the EDFAs are pieces of equipment completely separated from the fiber - you get a normal strand of fiber dug into the ground, and once you want to amplify it, you've got to plug it into an EDFA line card with the erbium-doped fiber already contained in it. In the sea, those systems are way more integrated and the fiber is usually spliced right into the amplifier. I might be able to dig up a card tomorrow if you're curious as to how the system looks.
    - MacroChip 8y ago
      Yes please! Thank you
    - lb1lf 8y ago

ioulian 8y ago

1: I think they don't put that thin cable on the seafloor, they are bunched together, in a much bigger cable with a lot of stuff around it [0] to protect it. About the patching, they say that in the article: they sometimes cut the cable (in case of a bad weather) and attach it to a buoy. So they can "patch it" ;) [0] http://2oqz471sa19h3vbwa53m33yj-wpengine.netdna-ssl.com/wp-content/uploads/2017/08/cable-cross-section.jpg http://2oqz471sa19h3vbwa53m33yj-wpengine.netdna-ssl.com/wp-c...

jlgaddis 8y ago

I'm on an iPad at the moment so I can't give you a direct link to any videos, but search for Hibernia Atlantic on Youtube. They have some short videos showing how the cables are laid, repaired, and so on.

rassibassi 8y ago

Recent graduate in Optical Communications here :) 1) The fiber is pretty thin, but there are several fibers combined in one transoceanic cable, see here https://en.wikipedia.org/wiki/Submarine_communications_cable https://en.wikipedia.org/wiki/Submarine_communications_cable. They don't patch them, but splice the fibers. Patching introduces a little loss, so it should be avoided. 2) Not sure how deep they are buried, but I think to remember that the shore end of a submarine cable is better protected than the part in the deep ocean. Due to more ship traffic at the coast etc. 3) Good question. The loss of an optical fiber is roughly 0.2 dB/km. Across the ocean the optical signal must be amplified several times (every 80-100km). Nowadays the amplification is all optical (EDFA or Raman). Before there were electrical regeneration schemes. Check out the history of the field, it's is quite interesting [1]. 4) Not sure how much data such a cable can carry, since it depends on how many fibers are deployed within. However, there are multiple interesting things to look into here. In research labs, people are investigating multicore/multimode fibers (space division multiplexing) [2], these fiber have incredible capacity. Personally, I think the most interesting metric is the spectral efficiency, so how much data can be transmitted per second per Herz. Such a metric is independent of multiplexing schemes over space/wavelength/time, and improvements have to come from better devices, signal processing or signal shaping methods [3]. Another mind-blowing area is using the nonlinear Fourier transform for better signaling methods [4]. Feel free to ask more questions :) and checkout the two biggest conferences for more in depth info. https://www.ofcconference.org/en-us/home/ https://www.ofcconference.org/en-us/home/ https://www.ecocexhibition.com/ https://www.ecocexhibition.com/ [1] https://www.osapublishing.org/oe/abstract.cfm?URI=oe-26-18-24190 https://www.osapublishing.org/oe/abstract.cfm?URI=oe-26-18-2... [2] Multicore: https://ieeexplore.ieee.org/abstract/document/7341685 https://ieeexplore.ieee.org/abstract/document/7341685 Multimode: https://www.osapublishing.org/abstract.cfm?uri=ofc-2018-Th4C.4 https://www.osapublishing.org/abstract.cfm?uri=ofc-2018-Th4C... Multimode+core: https://ieeexplore.ieee.org/document/8535233 https://ieeexplore.ieee.org/document/8535233 [3] https://arxiv.org/abs/1606.04073 https://arxiv.org/abs/1606.04073 [4] https://www.osapublishing.org/optica/abstract.cfm?uri=optica-4-3-307 https://www.osapublishing.org/optica/abstract.cfm?uri=optica...

lprd 8y ago
Looks like I got some reading material for tonight! Really appreciate your response, this is all very fascinating to me. Cheers :)

apaprocki 8y ago

4. Undersea should be the same as under land — 9.6Tbps, 96 100Gbps fibers.